R-Sport B21AT turbo build

jamesinc · 2020-08-09T12:44:17+00:00

The B21 engine was, after all, the power behind the 1986 ATCC winner. What are your plans for it - NA, old school K-Jet turbo, Volvo Turbo Cup carb turbo, or...

jamesinc

Okay mockup pipes are finished. Now to figure out how to make/have someone make the actual ones. Anyone have experience with this sort of thing?

jamesinc

Okay so I went down to Pirtek today and they can do 12mm steel pipe with a 38mm radius. The bends you see in these photos are about 30mm. They wanted about $80 for the two pipes so I left it with them to make a copy. The guy who does it will be in tomorrow, I asked him to give me a call beforehand and I'll see if he wants me to bring the block down so he has a fixture to work with.

Ex850R

It is amazing what those guys can do , ive seen (them (instrument fitters and the like) bend up a bit of wire of which goes which way , looks like an iso drawing , a few measurements and they come back with the spool and fit it off! .... you gave him an example to follow he will be fine.

jamesinc

Pirtek hooked me up. The last step is to braze the fittings on, another forum member has offered to help me with this.

Major Ledfoot

Nizze. So shiny!

The clean sump pan bolts and a few others look like they've been zinc dipped.

jamesinc

Major Ledfoot
Nizze. So shiny!
The clean sump pan bolts and a few others look like they've been zinc dipped.

Those are all new bolts, I'm missing a lot of fasteners for this block as it didn't come with that many to begin with and others I've stolen for other projects over the years.

That reminds me, I don't have head bolts! (Edit: actually I'm pretty sure I have a box of used head bolts somewhere...)

Ex850R

That looks dead sexy !

jamesinc

This build teaches much about patience. I haven't had much time in the garage lately, and what time I have had has been taken up by other Volvos.

I have sourced a 405 head in reasonable condition, and with Black Friday upon us I pulled the trigger on some more parts, the most important of which is the B21 head gasket/seal kit. Next steps will be to clean up the head and get it mated to the block. I'll probably take the time to port match seeing as this build is moving somewhat glacially ?

joshhhhhhugo

This is a very cool build @jamesinc! What ignition system are you planning on running?

jamesinc

joshhhhhhugo
This is a very cool build @jamesinc! What ignition system are you planning on running?

I'm going to re-use the 123/TUNE ignition that I have in the B21E currently in the destination vehicle. It can boost reference the advance up to 1 bar which will be more than enough for this application. I'll program in the factory B21A curve with -1 degree per 1 psi of boost and go to a dyno to dial it in further.

joshhhhhhugo

jamesinc
https://ozvolvo.org/discussion/comment/184473#Comment_184473
I'm going to re-use the 123/TUNE ignition that I have in the B21E currently in the destination vehicle. It can boost reference the advance up to 1 bar which will be more than enough for this application. I'll program in the factory B21A curve with -1 degree per 1 psi of boost and go to a dyno to dial it in further.

Nice, definitely sounds like the way to go from what I've read. Looking forward to see how this build progresses! Cheers.

jamesinc

Tore the head down today, it needs to go to the shop to be welded and surfaced.

While I had it apart I decided to tidy the head up a bit, I gasket-matched the ports and rounded out the bottom knee of the port on the exhaust side. I went over everything with sanding drums to clean it up and smooth out the casting surface generally.

I think I'll have to get new valve stems for it. The valves themselves are dirty but in good condition, they all measured between .313" and .314", which is in-spec.

whitedragon64

Hi James -new guy here, Mate you have these welsh plugs in backwards The concave face faces outwards

Nice build so far by the way top job ?️

ramrod

No he doesn't

This is a B21

Not B230

whitedragon64

Yes of coarse my bad disc type not the cup type

jamesinc

@whitedragon64 yeah as ramrod says these are the dome-type, so they started convex and they've been caved in a bit with a socket and a mallet to seat them.

PS welcome to the forums!

whitedragon64

Cheers James

jamesinc

I am currently muddling my way through head gasket selection. The 405 head's chamber overlaps the B21 head gasket ever-so-slightly on the exhaust valve side. It's the right size for the bore so will have to compare the chamber on the 405 to the B21A stock 160 chamber. I might just fit the head and look in from underneath to see how it lines up, although that would be a pain because the bottom end is already assembled.

Worst-case scenario I will scrap the 405 head and use a 160 head, although hopefully I can avoid that as it will require redoing the head from scratch.

Philia_Bear

If using a b23 spec head on the b21 spec block you must use the b23 spec gasket

You just end up with extra quench pads all the way around and a slightly lower cr

jamesinc

Philia_Bear
If using a b23 spec head on the b21 spec block you must use the b23 spec gasket
You just end up with extra quench pads all the way around and a slightly lower cr

Yeah my machinist was of similar opinion, we test-fit a B230 gasket and a B21 gasket and the B230 one was the better fit. He said ideally we'd use a gasket size about halfway between the two but I think I'll just run a B23 gasket

VolvoHordz

Yeah I'd just run a b23 gasket.

« Previous Page Next Page »